Machines. Technologies. Materials.
Vol. 9 (2015), Issue 8

Table of Contents

  • RESEARCH OF THE DIESEL ENGINE FAILURE DEPENDENCY ON ENGINE OPERATING CONDITIONS

    pg(s) 3-7

    the paper deals with the analysis of the factors and aspects covered by the Diesel Engine Reliability Theory and relevant for the discussion of engine reliability. The paper suggests and examines indicators for the assessment of engine reliability, and quantitative function for the evaluation of engine technical condition. The integrated effect of mountainous dessert on automotive engines is also examined although it has received little research attention so far, whereas findings of quantitative criteria analysis intended for reliability assessment under difficult conditions have not been publicly reported as they have been accomplished by manufacturers of military vehicles.

    Engine operating conditions refer to the manner of engine use, intensity of engine operation, different types of engine loads and their sequence, as well as culture and qualification of drivers, servicemen and maintenance personnel, provision of repair and diagnostics equipment, etc.

    Research of the case under consideration has been accomplished in mountainous desert of Afghanistan showing complicated climatic conditions. For the purpose of collecting precise and accurate data, vehicles used by the Provincial Reconstruction Team situated in Ghor province (Afghanistan) were selected for the research. Their operation course, failures, and repairs can be tracked and captured more precisely than those of civilians as their data are recorded in data logs.

  • A STUDY OF CHARGE STRATIFICATION IN THE TWO-STROKE ENGINE WITH GASOLINE INJECTION

    pg(s) 14-17

    Charge stratification of the combustible mixture through separate input of air and gasoline in the two-stroke gasoline engine is studied. Clean air enters the upper part of the vent channels through the check valve plate and then goes into the crank camera. The mixing occurs in the crank chamber and is controlled by the time and duration of the fuel injection nozzle. Before blowing cylinder volumes of the purge channels are filled mostly with clean air. The volume of the crank chamber is filled with a mixture of gasoline and air. Blowing the working volume of the cylinder is carried out mostly by clean air volumes from the purge channels. The process of purging is completed by filling the cylinder with fresh mixture from the crank chamber. Layer-by-layer purging of the cylinder greatly reduces the direct losses of fuel into the exhaust system. This leads to increased fuel efficiency of the two-stroke engine and reduces environmental pollution. Maximum power is achieved for mixtures with air ratio α =1.0, the best efficiency on the poorer mixtures with α =1,2-1,25. In this case the reduction of fuel consumption is up to 20 %.

  • EXPERIMENTAL DETERMINATION OF DISTILLATION CURVES OF ALCOHOLS/GASOLINE BLENDS AS BIO-FUEL FOR SI ENGINES

    pg(s) 18-21

    The use of oxygenates as a gasoline blend is one of production methods for high octane gasoline and reduction of harmful compounds amount in exhaust gas. Distillation curves are presented for single monohydroxy alcohols and gasoline mixtures containing 3- 15% by volume of ethanol, 1-butanol and i-butanol (2-methyl-1-propanol) which can be obtained from renewable sources. The influence of various concentrations of these alcohols on the distillation characteristics of base gasoline were investigated. Most alcohols form mixtures with gasoline exhibiting near-azeotropic behavior near its boiling point that significantly affect the shape of the distillation curves. In addition, distillation curves for a variety of dual-alcohol blends are presented, containing 10-20% by volume of two alcohols.

  • FUNCTIONALITY OF THE STIRLING ENGINE WITH NONCONVENTIONAL MECHANISM FIK

    pg(s) 22-25

    At the design of heat engines like Stirling engines are, it is possible to use not only classical crank mechanisms, but also non-conventional mechanisms. Engines with non-conventional mechanisms may have several advantages when used in practice, but the design calculation model is often more difficult. This paper deals with the design of the measuring system for the measurement and diagnostic of basic parameters of the thermal cycles in Stirling engine with nonconventional FIK mechanism, which was solved in the project VEGA: Nonconventional engine FIK – Stirling. The measuring system concept is applied to a special type of piston machines with swinging mechanism that is used in this instance of a Stirling engine type. Stirling engines are currently usually used as a drives of machines for production of the electricity. There are several types of mechanisms, which are suitable by design for use in a Stirling heat engine. FIK mechanism is a swinging system, which is characterized by circular motion of the central point of the swinging plate during the rotation of the shaft. Proposed measuring systems allows to confirm the functionality of the structural design of Stirling engine with a swinging plate and examine the thermodynamic phenomena conducted in the engine cylinders.

  • TESTING THE EFFICIENCY OF INTERNAL COMBUSTION CATALYSTS PO-SITION MODEL.

    pg(s) 26-28

    In order to determine the effectiveness of the catalytic coating applied to the engine valve, a study model. For this purpose built test stand made of elements of the real engine. The catalyst temperature was controlled by electric heating. The position of the working gas fumes were collected with a spark-ignition engine, idling. Performed a simultaneous measurement of gas composition at the inlet to the model and the output from the system. The study was conducted at a constant flow rate and variable temperature exhaust gas catalyst sys- tem. The results of the study are presented in the form of comparative charts. It has been found highly effective activity of the catalyst for carbon monoxide and relatively high efficiency for hydrocarbons. Measurements of nitric oxide levels showed no significant changes in concentration in a range of temperatures.

  • COMPARISON OF CHARACTERISTICS OF SPARK PLUG ENGINES FSI, TSI/TFSI TYPE OF VOLKSWAGEN COMPANY

    pg(s) 32-34

    The use of direct injection in spark ignition engines, significantly facilitated the use of chargers in these engines. This resulted lately in the significant popularization of direct injection engines, initially freely sucking and in final result turbocharged. The greatest popularity on the market gained engines of Volkswagen company, named FSI and TFSI / TSI. Application of Common Rail systems allowed not only to improve the characteristics of the engine by increasing the accuracy in dispensing fuel into individual cylinders. The most important gain is the possibility of second injection of the fuel to the cylinder after the intake valve is closed. On the one hand it allows better control of the load in the cylinder, at first with the piston crown, and now with shaping the injection by the injector.

  • ENERGY SAVING IN THE HYDRAULIC CIRCUIT FOR AGRICULTURAL TRACTORS: FOCUS ON THE POWER SUPPLY GROUP.

    pg(s) 35-41

    This work aims to analyze a complete hydraulic system of a medium size agricultural tractor, in order to perform an energy dissipation analysis and to suggest possibly alternative configurations and solutions. The fuel consumption and energy dissipation in off road vehicles have in fact become a key feature, given the great attention devoted to the need of reducing pollutant emissions, in order to satisfy the future emission limits. In this work the focus is on the fluid power supply group and the standard architecture of this unit has been compared with an alternative solution, called variable pump margin strategy and compared on the basis of the power consumption to perform the same duty cycle, showing that a relevant percentage of energy may be saved with simple modifications in the hydraulic power generator group.

  • USING OF WASTE HEAT OF INTERNAL COMBUSTION ENGINES AND DRAFT OF EXHAUST GAS HEAT EXCHANGER.

    pg(s) 42-45

    Article discusses about the use of heat exchangers for stationary combustion engines and cogeneration units. The paper is dedicated to the problem of unused thermal energy in stationary engines. It analyses possibilities of accumulation of heat energy and its possible application in various fields. The paper deals with the classification of heat exchangers and with the subsequent description of design solutions of heat exchangers types used in given field. Resolves draft of exhaust gas heat exchanger according to the required parameters of internal combustion engine and subsequent simulation in the simulation program Comsol multiphysics to verify the correctness of the design and the construction solution of the exhaust gas heat exchanger for stationary combustion engines.

  • MONITORING TECHNICAL CONDITION OF ENGINE BASED ON THE RESULTS OF DIAGNOSTICS TRIBOTECHNICAL

    pg(s) 46-48

    The article deals with monitoring of chemical elements during lifetime of military vehicles engine oil. Tribotechnical diagnosis is non-destructive and non-dismantling diagnostic method used lubricating oil as a source of information about the processes and changes in the mechanical systems to which it is applied. The paper deals with mathematical processing, tracking and analyzing data obtained from measurement tribo – diagnostics. For the analysis were used following methods AES and FTIR to monitor chemical elements, additives and contamination in engine oil. The increase in the metals and reduce the amount of additives were specially observed. The results were modelled using mathematical models to the value of the correlation coefficient R. The models can be used to predict the engine oil in the same or similar aggregates petrol engines.

  • THE GAS TURBINE ENGINES OPERATIONAL PERFOMANCES MATHEMATIC SIMULATION METHOD

    pg(s) 49-52

    The gas turbine engine operational performances definition method based on blade–to-blade mathematic simulation of multistage axial compressor and high temperature cooling transonic multistage turbine using flow paths and middle radius blades geometric parameters is shown. The method allows to take into account air bypass and bleeding from compressor for the cooling and its blowing into turbine and their influence on the engine parameters.
    As example, attained by calculation way the results of turbo-shaft engine operational performances and air by pass bleeding from compressor influence on the engine specific parameters, efficiency and stability margin are represented.

  • METHODS OF AVIATION GAS TURBINE ENGINES COMPRESSORS COMPUTATIONAL INVESTIGATIONS

    pg(s) 53-56

    The prediction methods for calculating of different compressor objects developed at the department of aircraft engines theory of National Aerospace University named after N. E. Zhukovsky "Kharkov Aviation Institute" are presented. Results of computational studies for various compressor objects such as high-pressure fan stage, multistage axial compressors of GTE in a wide range of flow rates and rate of are rotation modes and high pressure centrifugal stage with taking into account the air – bleeding and bypass from compressor setting shown. The Mach number flow isolines near the stability boundary, on the line of operating modes and near the compressor locking are demonstrated. Numerical investigation results of sub- and transonic flow fields and summary performances in high pressure centrifugal stage are presented and the flow features in its elements and its modification results are examined.

  • ENGINE COOLING SYSTEM WITH ENERGY RECUPERATION

    pg(s) 57-59

    Internal combustion (IC) engines are main source of power used in the automotive industry. These engines have undergone many up gradation for decades, with an initial goal of increase in power of the unit. Presently, as a result of tightening environmental regulations, research is focused on reducing harmful gases emissions along with increase of the engines efficiency.

  • ADVANCED TECHNOLOGIES FOR WASTE HEAT RECOVERY IN INTERNAL COMBUSTION ENGINES

    pg(s) 60-66

    The escalating fuel price and carbon dioxide legislation have renewed the interest in the methods of increasing engine thermal efficiency beyond in-cylinder techniques. The aim of this study is to review the latest technologies of waste heat recovery of exhaust gases in internal combustion engines. These include turbocompounding systems, thermoelectric generators, thermoacoustic systems and closed-loop thermodynamic cycles based on Stirling, Ericsson and Rankine cycles. A number of studies revealed that Rankine cycle is the most perspective waste heat recovery system due to its higher thermal efficiency. Finally, the components of the Rankine cycle (working fluid, evaporator and expander) were studied in detail.

  • DIAGNOSTIC OF A TURBOCHARGED DIESEL ENGINE

    pg(s) 67-70

    The paper deals with non-dismountable diagnostic of the power of a turbocharged Diesel engine. For the purposes of diagnostic the transient operation mode of the engine was described by an extended mathematic model that takes into account the influence of suction volumes and exhaust pipes. The results obtained by this improved model were similar to the values measured by an experiment. This model produces relatively more trustworthy information regarding the influence of some typical defects on the chosen diagnostic parameters. Finally, the improvement makes possible to more accurately identify them, on the basis of changes of selected and measured diagnostic quantities the defect that has caused these changes.

  • NUMERICAL SIMULATION OF THE METHANE INJECTION PROCESS IN THE INLET MANIFOLD OF A DIESEL ENGINE

    pg(s) 71-75

    The main purpose of this paper is a numerical simulation of methane injection process in the inlet manifold of a compression ignition engine. The paper gives an overview of issues related to the turbulence modeling. Computational resources such as the amount of time for the simulation and the memory of the individual models were discussed. While it is impossible to state categorically which model is the most appropriate for a specific application, general guidelines are presented in order to help you choose the turbulence model for the flow you want to model.